A Retrospective Analysis to Evaluate Role of the New UTD Classification System in Prenatal Prediction of Severity and Postnatal Outcome in Antenatally Diagnosed Urinary Tract Dilatation Abnormalities.

BACKGROUND/PURPOSE OF THE STUDY: Foetal urinary tract dilation (UTD) abnormalities affect 1-5% of all pregnancies. However, exact incidence is difficult to estimate because of different terminologies used to define the condition and different grading systems to define its severity antenatally as well as postnatally worldwide. In order to overcome this problem, the new UTD classification system has been introduced in the year 2014 so as to have universal approach for diagnosis and management of UTD globally. Indian data about clinical utility of the UTD classification system and its role in prenatal prediction of severity of renal disease are lacking. The present study aims to investigate clinical utility of new UTD classification system in foetal UTD abnormalities and to evaluate the role of UTD classification system in antenatal prediction/prognostication of severity of UTD abnormalities.

METHODS: We conducted a single-centre retrospective study between April 2014 and January 2017, which included 70 infants with antenatally diagnosed UTD delivered in our hospital and managed in our paediatric unit postnatally. Pre- and postnatal ultrasound findings were noted, and UTD-A and UTD-P classification were applied retrospectively in all cases as per criteria defined in the new UTD classification. Postnatal outcome in all cases was evaluated in terms of need for immediate postnatal urosurgical intervention, presence of persistent UTD pathology and severity of renal impairment in relation to their pre- and postnatal UTD A and P risk categories.

RESULTS: None from UTD A1 risk group in the last prenatal scan showed significant postnatal UTD abnormality. In contrast to this, UTD A2-3 risk group in the last prenatal scan had persistent postnatal UTD pathology in 70% cases. All infants with abnormal postnatal UTD diagnosis were identified prenatally as UTD A2-3 (high risk). Nine infants (12.8%, n = 70) who needed urosurgical intervention postnatally were categorised as UTD A2-3 prenatally and UTD P3 postnatally.

CONCLUSION: We found increased frequency of complications and urosurgical interventions in all infants with antenatal UTD A2-3 grades in the last prenatal scan in comparison with those with UTD A1 grades who showed complete resolution (100%) postnatally. Antenatal UTD classification may be useful in antenatal prediction and prognostication of postnatal severity, especially in high-risk cases (i.e. UTD A2-3).